To a mixture of potassium carbonate (6.2 g), sodium acetate trihydrate (19 g), water (100 ml) and dioxane (100 ml) was added 1-(3'-diethylaminopropoxy)-2,4-diaminobenzene trihydrochloride (10.4 g) immediately followed by adding benzoyl chloride (13 g) while cooling with ice, and thereafter, the resulting mixture was stirred at room temperature for 2 hours. Then, after the addition of water (500 ml), the pH of the mixture was adjusted to 9 - 10 and the precipitated crystals were recovered by filtration. After washing the crystals with water, they were recrystallized twice from methanol-water to obtain 7.9 g of 1-(3'-diethylaminopropoxy)-2,4-bis(benzamido)-benzene having a melting point between 139° and 140° C.
